Background Info
What is the difference between monozygotic and dizygotic twins?
Monozygotic twins are identical - one egg split into two
Dizygotic twins are fraternal - two separate eggs
How were the interviews conducted?
Over the phone
Were there any correlation between the years the twins lived together and lifetime major depression?
No
What is a limitation to using twin studies?
Environmental factors cannot be eliminated.
Twins are rarely separated at birth, and forcefully separating them is a violation of ethics.
Behavioral traits are rarely 100% coordinated
They cannot directly measure genetics
Where did this study take place?
Sweden
What criteria was used to assess participants?
DSM-IV (diagnostic and statistical manual) criteria for depression
What was the estimated heritability of major depression?
0.38
Is there a possibility of researcher or participant bias?
Yes - All data and information comes from the mouth of participants
What is one content link that could be used for this study?
Genes and behavior
Twins
Genetic similarity
Research with biological approach
Genetic inheritance
What is an individual environment?
Personal life events that one twin experiences but not the other
higher
Are there any sampling issues
No - a large sample is used
Describe
What is a shared environment?
Experiences shared by both twins
Were concordance rats for major depression higher in women or men?
Women
What variables were isolated?
None - no cause and effect relationship can be determined
What command term requires you to propose a solution, hypothesis or possible answer?
Suggest
What kind of questions were asked?
-Shared and individual environments
- history of antidepressant treatment
-Symptoms of major depression
Are there any significant differences seen in roles of genetic and environmental factors in major depression?
No significant differences
Are the findings of the study reliable?